The most lucrative postal code in Montreal during the 2022-23 fiscal year was by far the H3A postal code.
This was a result of 2 large government contracts awarded for the construction of the new Champlain Bridge which was completed in 2019. These 2 contracts, worth $5.0 billion and $4.2 billion respectively, were awarded to the "Groupe Signature Sur Le Saint Laurente" and the "Esap Project Co Limited Partnership" for engineering consultancy services and construction services. The contracts may be found here: Link 1 (Groupe Signature) Link 2(Esap Project Co)